Remember the patent story I wrote a year and a half ago that predicted all the latest wireless Di2 derailleurs, or the one more than two years back that teased 13-speed Shimano cassettes? Well, that early tease is getting supported by several recent partial slip-ups from several different companies in the bike industry. And it all points to a new Shimano GRX 1x 13-speed update on the near horizon, possibly with Dura-Ace 13-speed coming not far behind?So what do we know?Is Shimano going 13-speed with a new MicroSpline Road freehub?Bikerumor GRX 13 mockupAbout a week ago, DT Swiss revamped their affordable aluminum 1800-series of road, endurance all-road & gravel bike wheels. Out of those three separate disciplines, only one, the gravel G1800, included a slightly new reference to a previously-unannounced freehub standard. DT called it MicroSpline Road in their press kit. We could have written that off as no big deal if there wasnt anything else floating around. Plenty of Shimano gravel groupsets were already using MicroSpline since GRX 112 shares wide-range MTB cassettes on MicroSpline freehubs.So why a separate MicroSpline Road?It turns out the next one to reveal a bit more was German online retailer Bike-Discount.de. They listed those new DT Swiss G 1800 Spline wheels with a bit more detail on freehub options, and some telling freehub body product codes. In addition to classic SRAM XDR (AXDR) & Shimano HG 11s (ASF11), we see two other options with very similar codes: Shimano MicroSpline 12s (ASL12R) & Shimano 13-speed (ASL13R).The 12-speed MicroSpline seems to be the current MTB standard, and the new ASL13R appears to be the next-level progression that DT was calling MicroSpline Road. Similar product numbers would make sense for both being the same spline pattern. But this one goes to 13!Why, you ask?Bikerumor Shimano 13sp cassette mockupPerhaps a new 13-speed MicroSpline road freehub needs more space to fit that extra gear? Shimano, SRAM & Campagnolo have all used a few tricks in the past to fit more cogs of the same width in the same spacing before sometimes pushing those cogs closer to the frame/dropout surface, and sometimes cantilevering them over hub flanges & spokes. The fact that Shimano would need another, slightly different freehub body suggests they couldnt find more space with the existing MicroSpline, and needed to push it a bit furtherShimano 13-speed isnt guaranteed, but its not just speculation eitherShimano has been teasing us with 13-speed cassettes in the patent drawings for at least two years. They could have easily put 12 cogs on that cassette if they werent trolling us.And in the meantime, both SRAM and Campagnolo have launched 13-speed gravel & road groupsets. So, its high time for Shimano to catch up.When is it coming to gravel? And when will Shimano 13sp hit the road?Thats something we dont know. Shimano hasnt told us when to expect a new dropbar groupset. Frankly, with fairly recent GRX 12-speed launches, we wouldnt have expected a new Shimano gravel launch any time soon. But the fact that DT Swiss is debuting this new freehub body option only on their gravel wheels (and clearly not on the road & all-road variants) suggests gravel is likely to get 13-speeds first. That probably does make the most sense, giving more range or smoother gearing steps to 1x drivetrains.Yet really, weve been waiting for a new Dura-Ace groupset for several years. DT is calling the new 13sp freehub MicroSpline Road which sounds to us like its laying the groundwork for a 13-speed road groupset, too. The fact that we didnt see it on pro bikes at this years Tour de France suggests it likely wont be ready until at least next spring.But lets just say that Shimano & DT have piqued our interest. And well be keeping our eyes open to spot an extra cog on pro road and gravel bikes over the next few months!bike.Shimano.com